1.1 Field of the Invention
The present invention relates to a process for manufacturing highly functional activated carbon fibers having oxygen functional groups introduced onto the surface thereof by anodic oxidation, the product resulting from this process and the use of this product. More specifically, it relates to a process for manufacturing activated carbon fibers having greatly improved adsorption performance time and adsorption performance when in contact with surface oxides such as in the case where gas and liquid impurities are treated by an anodic oxidation treatment of conventional activated carbon fibers by electrochemical techniques using an acidic and alkaline solution as an electrolyte.
1.2 Description of the Prior Art
As pollution of the environment has become a public concern, the removal of liquid and gas impurities has become a public demand. Under such circumstances, the development of improved adsorbents to meet such demands is urgently needed.
The activated carbon fibers have highly specific surface area and surface reactivity, good adsorptivity and micropores. They have been widely used in waste water and sewage disposal apparatus in houses and industrial facilities, apparatus for removing harmful gases in the facilities for manufacturing semiconductors and precision measuring machines, anti-gas masks for military use and general industrial use and air cleaning apparatus in offices and houses.
The activated carbon fibers have been used for the purpose of purification, collection and separation in many fields. They are organic adsorbents in a saturated binding form and have the well-developed micropores, which are the barometers for evaluating adsorptivity as adsorbents, as compared to inorganic adsorbents of an unsaturated binding form such as silica gel, alumina gel and synthetic zeolite. They also show a good molecular sieve effect, because they have a further broader adsorption surface area and a comparatively regular size of micropore as compared to conventional carbon fibers, the shape of which is restricted to a granular or powder form. In addition, they have good stability, cyclability, and processibility clue to a fiber form, thereby the demand for such carbon fibers gradually increases.
The conventional methods for improving the performance of activated carbon fibers include methods for introducing functional groups onto activated carbon fibers such as:
However, these methods have several problems. The surface structure and surface properties of the activated carbon fibers may depend on activating temperature and time, however, it is difficult to control time and temperature. Since side reactions may be caused where surface treatment is conducted in a high temperature gas, many apparatus and costs for inhibiting those side reactions are needed. In addition, since the surface functional groups attached to the surface of the activated carbon fibers are not able to continuously display their function, the adsorption performance thereof is unsatisfactory.